The present invention relates generally to all terrain vehicles having a straddle-seat for accommodating a rider and a set of handle bars for receiving the hands of the rider. More particularly, the present invention relates to suspension and steering systems for all terrain vehicles.
In recent years, all terrain vehicles (ATVs) have gained widespread popularity. ATVs are commonly used in hunting, trail riding and utility applications such as the wide variety of maintenance activities which take place on a farm. Attachments are available for ATVs for use in utility applications such as plowing snow, mowing grass and hauling materials.
Perhaps the most common ATV application is trail riding. Trail riding on an ATV allows an ATV enthusiast to travel through areas which are not accessible by ordinary automobiles. Modern ATVs, can cover ground very rapidly and can cover great distances. Frequently, ATV enthusiasts ride their ATV for many hours straight and cover many miles. If the rider is subjected to excessive jarring while traveling over rough terrain, operator fatigue may result particularly during a long ride. During such long rides, an ATV may be used to carry a rider through a wide variety of terrain. Terrain which may be encountered includes forests, swamps, and deserts. Frequently ATVs are called upon to travel across rugged terrain at relatively high speeds.
Part of the thrill of riding an ATV is encountering challenging terrain, and through the performance of the ATV and the skill of the rider passing through the terrain. The ability to tackle challenging terrain may depend on the performance of the steering systems, suspension, and the interface between the rider and the ATV. These elements each effect the riding experience enjoyed by the ATV enthusiast.
The present invention relates generally to all terrain vehicles having a straddle-seat for accommodating a rider and a set of handle bars for receiving the hands of the rider. More particularly, the present invention relates to suspension and steering systems for all terrain vehicles. An ATV in accordance with the present invention may include a frame and a wheel carrier for rotatably supporting a wheel.
In certain implementations, the present invention comprises a steering system including a steering column. A steering arm is fixed to the steering column proximate a proximal end thereof. In certain implementations, a pair of handle bars are fixed to the steering column proximate a distal end thereof. In one aspect of the present invention, the proximal end of the steering column is rotatably supported by a mounting bracket. In certain implementations, the mounting bracket also rotatably supports a left intermediate arm and a right intermediate arm. The left intermediate arm may be advantageously coupled to the steering arm by a left link, and the right intermediate arm may be coupled to steering arm by a right link.
The steering system may also include a left tie rod and a right tie rod. Each tie rod may be pivotally coupled to a protrusion of a wheel carrier at an outer joint of the tie rod. Each tie rod may also be pivotably coupled to an intermediate arm at an inner joint of the tie rod. The steering system may be used to rotate a wheel carrier about a steering axis of the wheel carrier. In a preferred embodiment, a suspension and steering system is provided which is dimensioned so that movement of the suspension through its travel between a full extension position and a full compression position is unlikely to cause rotation of the wheel carrier about the steering axis. In an advantageous implementation, the inner joint of each tie rod is located so that rotation of the wheel carrier about the steering axis due to deflection of the suspension will be minimized.
Methods in accordance with the present invention may be used to locate a desirable position for the inner joint of each tie rod. A method for identifying the desirable location may include the steps of defining a first reference plane associated with a full compression position of the suspension, defining a second reference plane associated with a full extension position of the suspension, and identifying a reference line formed by an intersection of the first reference plane and the second reference plane.
A position may be selected proximate the reference line as the desirable position for the inner joint. In certain implementations, the inner joint is located so that the reference line intersects the inner joint. In some cases, the inner joint may be advantageously located so that the reference line intersects a center of the inner joint. In other cases, the inner tie rod joint may be located so that the center of the inner joint is disposed within a reference cylinder centered on the reference line.
In certain implementations, the step of defining the first reference plane comprises the steps of locating an instant center axis of the suspension when the suspension is at full compression and locating of a central point of the outer joint of the tie rod when the suspension is at full compression. In these implementations, the first reference plane is defined by the instant center axis and the central point located for the suspension at full compression.
In certain implementations, the step of defining the second reference plane comprises the steps of locating an instant center axis of the suspension when the suspension is at full extension and locating of a central point of the outer joint of the tie rod when the suspension is at full extension. In these implementations, the second reference plane is defined by the instant center axis and the central point located for the suspension at full extension.